1 /* Data structure definitions for a generic GCC target.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
5 This program is free software; you can redistribute it and/or modify it
6 under the terms of the GNU General Public License as published by the
7 Free Software Foundation; either version 2, or (at your option) any
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 In other words, you are welcome to use, share and improve this program.
20 You are forbidden to forbid anyone else to use, share and improve
21 what you give them. Help stamp out software-hoarding! */
23 /* This file contains a data structure that describes a GCC target.
24 At present it is incomplete, but in future it should grow to
25 contain most or all target machine and target O/S specific
28 This structure has its initializer declared in target-def.h in the
29 form of large macro TARGET_INITIALIZER that expands to many smaller
32 The smaller macros each initialize one component of the structure,
33 and each has a default. Each target should have a file that
34 includes target.h and target-def.h, and overrides any inappropriate
35 defaults by undefining the relevant macro and defining a suitable
36 replacement. That file should then contain the definition of
39 struct gcc_target targetm = TARGET_INITIALIZER;
41 Doing things this way allows us to bring together everything that
42 defines a GCC target. By supplying a default that is appropriate
43 to most targets, we can easily add new items without needing to
44 edit dozens of target configuration files. It should also allow us
45 to gradually reduce the amount of conditional compilation that is
46 scattered throughout GCC. */
52 #include "insn-modes.h"
54 /* Types used by the record_gcc_switches() target function. */
57 SWITCH_TYPE_PASSED, /* A switch passed on the command line. */
58 SWITCH_TYPE_ENABLED, /* An option that is currently enabled. */
59 SWITCH_TYPE_DESCRIPTIVE, /* Descriptive text, not a switch or option. */
60 SWITCH_TYPE_LINE_START, /* Please emit any necessary text at the start of a line. */
61 SWITCH_TYPE_LINE_END /* Please emit a line terminator. */
65 typedef int (* print_switch_fn_type) (print_switch_type, const char *);
67 /* An example implementation for ELF targets. Defined in varasm.c */
68 extern int elf_record_gcc_switches (print_switch_type type, const char *);
73 /* The struct used by the secondary_reload target hook. */
74 typedef struct secondary_reload_info
76 /* icode is actually an enum insn_code, but we don't want to force every
77 file that includes target.h to include optabs.h . */
79 int extra_cost; /* Cost for using (a) scratch register(s) to be taken
80 into account by copy_cost. */
81 /* The next two members are for the use of the backward
82 compatibility hook. */
83 struct secondary_reload_info *prev_sri;
84 int t_icode; /* Actually an enum insn_code - see above. */
85 } secondary_reload_info;
87 /* This is defined in sched-int.h . */
92 /* Functions that output assembler for the target. */
95 /* Opening and closing parentheses for asm expression grouping. */
96 const char *open_paren, *close_paren;
98 /* Assembler instructions for creating various kinds of integer object. */
106 } aligned_op, unaligned_op;
108 /* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
113 bool (* integer) (rtx x, unsigned int size, int aligned_p);
115 /* Output code that will globalize a label. */
116 void (* globalize_label) (FILE *, const char *);
118 /* Output code that will globalise a declaration. */
119 void (* globalize_decl_name) (FILE *, tree);
121 /* Output code that will emit a label for unwind info, if this
122 target requires such labels. Second argument is the decl the
123 unwind info is associated with, third is a boolean: true if
124 this is for exception handling, fourth is a boolean: true if
125 this is only a placeholder for an omitted FDE. */
126 void (* unwind_label) (FILE *, tree, int, int);
128 /* Output code that will emit a label to divide up the exception
130 void (* except_table_label) (FILE *);
132 /* Emit any directives required to unwind this instruction. */
133 void (* unwind_emit) (FILE *, rtx);
135 /* Output an internal label. */
136 void (* internal_label) (FILE *, const char *, unsigned long);
138 /* Emit a ttype table reference to a typeinfo object. */
139 bool (* ttype) (rtx);
141 /* Emit an assembler directive to set visibility for the symbol
142 associated with the tree decl. */
143 void (* visibility) (tree, int);
145 /* Output the assembler code for entry to a function. */
146 void (* function_prologue) (FILE *, HOST_WIDE_INT);
148 /* Output the assembler code for end of prologue. */
149 void (* function_end_prologue) (FILE *);
151 /* Output the assembler code for start of epilogue. */
152 void (* function_begin_epilogue) (FILE *);
154 /* Output the assembler code for function exit. */
155 void (* function_epilogue) (FILE *, HOST_WIDE_INT);
157 /* Initialize target-specific sections. */
158 void (* init_sections) (void);
160 /* Tell assembler to change to section NAME with attributes FLAGS.
161 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
162 which this section is associated. */
163 void (* named_section) (const char *name, unsigned int flags, tree decl);
165 /* Return a section for EXP. It may be a DECL or a constant. RELOC
166 is nonzero if runtime relocations must be applied; bit 1 will be
167 set if the runtime relocations require non-local name resolution.
168 ALIGN is the required alignment of the data. */
169 section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);
171 /* Return a section for X. MODE is X's mode and ALIGN is its
172 alignment in bits. */
173 section *(* select_rtx_section) (enum machine_mode, rtx,
174 unsigned HOST_WIDE_INT);
176 /* Select a unique section name for DECL. RELOC is the same as
177 for SELECT_SECTION. */
178 void (* unique_section) (tree, int);
180 /* Return the readonly data section associated with function DECL. */
181 section *(* function_rodata_section) (tree);
183 /* Output a constructor for a symbol with a given priority. */
184 void (* constructor) (rtx, int);
186 /* Output a destructor for a symbol with a given priority. */
187 void (* destructor) (rtx, int);
189 /* Output the assembler code for a thunk function. THUNK_DECL is the
190 declaration for the thunk function itself, FUNCTION is the decl for
191 the target function. DELTA is an immediate constant offset to be
192 added to THIS. If VCALL_OFFSET is nonzero, the word at
193 *(*this + vcall_offset) should be added to THIS. */
194 void (* output_mi_thunk) (FILE *file, tree thunk_decl,
195 HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
198 /* Determine whether output_mi_thunk would succeed. */
199 /* ??? Ideally, this hook would not exist, and success or failure
200 would be returned from output_mi_thunk directly. But there's
201 too much undo-able setup involved in invoking output_mi_thunk.
202 Could be fixed by making output_mi_thunk emit rtl instead of
203 text to the output file. */
204 bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta,
205 HOST_WIDE_INT vcall_offset,
208 /* Output any boilerplate text needed at the beginning of a
210 void (*file_start) (void);
212 /* Output any boilerplate text needed at the end of a
214 void (*file_end) (void);
216 /* Output an assembler pseudo-op to declare a library function name
218 void (*external_libcall) (rtx);
220 /* Output an assembler directive to mark decl live. This instructs
221 linker to not dead code strip this symbol. */
222 void (*mark_decl_preserved) (const char *);
224 /* Output a record of the command line switches that have been passed. */
225 print_switch_fn_type record_gcc_switches;
226 /* The name of the section that the example ELF implementation of
227 record_gcc_switches will use to store the information. Target
228 specific versions of record_gcc_switches may or may not use
230 const char * record_gcc_switches_section;
232 /* Output the definition of a section anchor. */
233 void (*output_anchor) (rtx);
235 /* Output a DTP-relative reference to a TLS symbol. */
236 void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);
240 /* Functions relating to instruction scheduling. */
243 /* Given the current cost, COST, of an insn, INSN, calculate and
244 return a new cost based on its relationship to DEP_INSN through
245 the dependence LINK. The default is to make no adjustment. */
246 int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);
248 /* Adjust the priority of an insn as you see fit. Returns the new
250 int (* adjust_priority) (rtx, int);
252 /* Function which returns the maximum number of insns that can be
253 scheduled in the same machine cycle. This must be constant
254 over an entire compilation. The default is 1. */
255 int (* issue_rate) (void);
257 /* Calculate how much this insn affects how many more insns we
258 can emit this cycle. Default is they all cost the same. */
259 int (* variable_issue) (FILE *, int, rtx, int);
261 /* Initialize machine-dependent scheduling code. */
262 void (* md_init) (FILE *, int, int);
264 /* Finalize machine-dependent scheduling code. */
265 void (* md_finish) (FILE *, int);
267 /* Initialize machine-dependent function while scheduling code. */
268 void (* md_init_global) (FILE *, int, int);
270 /* Finalize machine-dependent function wide scheduling code. */
271 void (* md_finish_global) (FILE *, int);
273 /* Reorder insns in a machine-dependent fashion, in two different
274 places. Default does nothing. */
275 int (* reorder) (FILE *, int, rtx *, int *, int);
276 int (* reorder2) (FILE *, int, rtx *, int *, int);
278 /* The following member value is a pointer to a function called
279 after evaluation forward dependencies of insns in chain given
280 by two parameter values (head and tail correspondingly). */
281 void (* dependencies_evaluation_hook) (rtx, rtx);
283 /* The values of the following four members are pointers to
284 functions used to simplify the automaton descriptions.
285 dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
286 returning insns which are used to change the pipeline hazard
287 recognizer state when the new simulated processor cycle
288 correspondingly starts and finishes. The function defined by
289 init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
290 to initialize the corresponding insns. The default values of
291 the members result in not changing the automaton state when
292 the new simulated processor cycle correspondingly starts and
294 void (* init_dfa_pre_cycle_insn) (void);
295 rtx (* dfa_pre_cycle_insn) (void);
296 void (* init_dfa_post_cycle_insn) (void);
297 rtx (* dfa_post_cycle_insn) (void);
299 /* The following member value is a pointer to a function returning value
300 which defines how many insns in queue `ready' will we try for
301 multi-pass scheduling. If the member value is nonzero and the
302 function returns positive value, the DFA based scheduler will make
303 multi-pass scheduling for the first cycle. In other words, we will
304 try to choose ready insn which permits to start maximum number of
305 insns on the same cycle. */
306 int (* first_cycle_multipass_dfa_lookahead) (void);
308 /* The following member value is pointer to a function controlling
309 what insns from the ready insn queue will be considered for the
310 multipass insn scheduling. If the hook returns zero for insn
311 passed as the parameter, the insn will be not chosen to be
313 int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
315 /* The following member value is pointer to a function called by
316 the insn scheduler before issuing insn passed as the third
317 parameter on given cycle. If the hook returns nonzero, the
318 insn is not issued on given processors cycle. Instead of that,
319 the processor cycle is advanced. If the value passed through
320 the last parameter is zero, the insn ready queue is not sorted
321 on the new cycle start as usually. The first parameter passes
322 file for debugging output. The second one passes the scheduler
323 verbose level of the debugging output. The forth and the fifth
324 parameter values are correspondingly processor cycle on which
325 the previous insn has been issued and the current processor
327 int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
329 /* The following member value is a pointer to a function called by the
330 insn scheduler. It should return true if there exists a dependence
331 which is considered costly by the target, between the insn
332 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
333 the dep that represents the dependence between the two insns. The
334 second argument is the cost of the dependence as estimated by
335 the scheduler. The last argument is the distance in cycles
336 between the already scheduled insn (first parameter) and the
337 the second insn (second parameter). */
338 bool (* is_costly_dependence) (struct _dep *_dep, int, int);
340 /* The following member value is a pointer to a function called
341 by the insn scheduler. This hook is called to notify the backend
342 that new instructions were emitted. */
343 void (* h_i_d_extended) (void);
345 /* The following member value is a pointer to a function called
346 by the insn scheduler.
347 The first parameter is an instruction, the second parameter is the type
348 of the requested speculation, and the third parameter is a pointer to the
349 speculative pattern of the corresponding type (set if return value == 1).
351 -1, if there is no pattern, that will satisfy the requested speculation
353 0, if current pattern satisfies the requested speculation type,
354 1, if pattern of the instruction should be changed to the newly
356 int (* speculate_insn) (rtx, int, rtx *);
358 /* The following member value is a pointer to a function called
359 by the insn scheduler. It should return true if the check instruction
360 corresponding to the instruction passed as the parameter needs a
362 bool (* needs_block_p) (rtx);
364 /* The following member value is a pointer to a function called
365 by the insn scheduler. It should return a pattern for the check
367 The first parameter is a speculative instruction, the second parameter
368 is the label of the corresponding recovery block (or null, if it is a
369 simple check). If the mutation of the check is requested (e.g. from
370 ld.c to chk.a), the third parameter is true - in this case the first
371 parameter is the previous check. */
372 rtx (* gen_check) (rtx, rtx, bool);
374 /* The following member value is a pointer to a function controlling
375 what insns from the ready insn queue will be considered for the
376 multipass insn scheduling. If the hook returns zero for the insn
377 passed as the parameter, the insn will not be chosen to be
378 issued. This hook is used to discard speculative instructions,
379 that stand at the first position of the ready list. */
380 bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (rtx);
382 /* The following member value is a pointer to a function that provides
383 information about the speculation capabilities of the target.
384 The parameter is a pointer to spec_info variable. */
385 void (* set_sched_flags) (struct spec_info_def *);
388 /* Functions relating to vectorization. */
391 /* The following member value is a pointer to a function called
392 by the vectorizer, and return the decl of the target builtin
394 tree (* builtin_mask_for_load) (void);
396 /* Returns a code for builtin that realizes vectorized version of
397 function, or NULL_TREE if not available. */
398 tree (* builtin_vectorized_function) (unsigned, tree);
400 /* Target builtin that implements vector widening multiplication.
401 builtin_mul_widen_eve computes the element-by-element products
402 for the even elements, and builtin_mul_widen_odd computes the
403 element-by-element products for the odd elements. */
404 tree (* builtin_mul_widen_even) (tree);
405 tree (* builtin_mul_widen_odd) (tree);
408 /* The initial value of target_flags. */
409 int default_target_flags;
411 /* Handle target switch CODE (an OPT_* value). ARG is the argument
412 passed to the switch; it is NULL if no argument was. VALUE is the
413 value of ARG if CODE specifies a UInteger option, otherwise it is
414 1 if the positive form of the switch was used and 0 if the negative
415 form was. Return true if the switch was valid. */
416 bool (* handle_option) (size_t code, const char *arg, int value);
418 /* Return machine mode for filter value. */
419 enum machine_mode (* eh_return_filter_mode) (void);
421 /* Given two decls, merge their attributes and return the result. */
422 tree (* merge_decl_attributes) (tree, tree);
424 /* Given two types, merge their attributes and return the result. */
425 tree (* merge_type_attributes) (tree, tree);
427 /* Table of machine attributes and functions to handle them.
429 const struct attribute_spec *attribute_table;
431 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
432 one if they are compatible and two if they are nearly compatible
433 (which causes a warning to be generated). */
434 int (* comp_type_attributes) (tree type1, tree type2);
436 /* Assign default attributes to the newly defined TYPE. */
437 void (* set_default_type_attributes) (tree type);
439 /* Insert attributes on the newly created DECL. */
440 void (* insert_attributes) (tree decl, tree *attributes);
442 /* Return true if FNDECL (which has at least one machine attribute)
443 can be inlined despite its machine attributes, false otherwise. */
444 bool (* function_attribute_inlinable_p) (tree fndecl);
446 /* Return true if bitfields in RECORD_TYPE should follow the
447 Microsoft Visual C++ bitfield layout rules. */
448 bool (* ms_bitfield_layout_p) (tree record_type);
450 /* True if the target supports decimal floating point. */
451 bool (* decimal_float_supported_p) (void);
453 /* Return true if anonymous bitfields affect structure alignment. */
454 bool (* align_anon_bitfield) (void);
456 /* Return true if volatile bitfields should use the narrowest type possible.
457 Return false if they should use the container type. */
458 bool (* narrow_volatile_bitfield) (void);
460 /* Set up target-specific built-in functions. */
461 void (* init_builtins) (void);
463 /* Expand a target-specific builtin. */
464 rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
465 enum machine_mode mode, int ignore);
467 /* Select a replacement for a target-specific builtin. This is done
468 *before* regular type checking, and so allows the target to implement
469 a crude form of function overloading. The result is a complete
470 expression that implements the operation. */
471 tree (*resolve_overloaded_builtin) (tree decl, tree params);
473 /* Fold a target-specific builtin. */
474 tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);
476 /* For a vendor-specific fundamental TYPE, return a pointer to
477 a statically-allocated string containing the C++ mangling for
478 TYPE. In all other cases, return NULL. */
479 const char * (* mangle_fundamental_type) (tree type);
481 /* Make any adjustments to libfunc names needed for this target. */
482 void (* init_libfuncs) (void);
484 /* Given a decl, a section name, and whether the decl initializer
485 has relocs, choose attributes for the section. */
486 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
487 unsigned int (* section_type_flags) (tree, const char *, int);
489 /* True if new jumps cannot be created, to replace existing ones or
490 not, at the current point in the compilation. */
491 bool (* cannot_modify_jumps_p) (void);
493 /* Return a register class for which branch target register
494 optimizations should be applied. */
495 int (* branch_target_register_class) (void);
497 /* Return true if branch target register optimizations should include
498 callee-saved registers that are not already live during the current
499 function. AFTER_PE_GEN is true if prologues and epilogues have
500 already been generated. */
501 bool (* branch_target_register_callee_saved) (bool after_pe_gen);
503 /* True if the constant X cannot be placed in the constant pool. */
504 bool (* cannot_force_const_mem) (rtx);
506 /* True if the insn X cannot be duplicated. */
507 bool (* cannot_copy_insn_p) (rtx);
509 /* True if X is considered to be commutative. */
510 bool (* commutative_p) (rtx, int);
512 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
513 rtx (* delegitimize_address) (rtx);
515 /* True if the given constant can be put into an object_block. */
516 bool (* use_blocks_for_constant_p) (enum machine_mode, rtx);
518 /* The minimum and maximum byte offsets for anchored addresses. */
519 HOST_WIDE_INT min_anchor_offset;
520 HOST_WIDE_INT max_anchor_offset;
522 /* True if section anchors can be used to access the given symbol. */
523 bool (* use_anchors_for_symbol_p) (rtx);
525 /* True if it is OK to do sibling call optimization for the specified
526 call expression EXP. DECL will be the called function, or NULL if
527 this is an indirect call. */
528 bool (*function_ok_for_sibcall) (tree decl, tree exp);
530 /* True if EXP should be placed in a "small data" section. */
531 bool (* in_small_data_p) (tree);
533 /* True if EXP names an object for which name resolution must resolve
534 to the current module. */
535 bool (* binds_local_p) (tree);
537 /* Do something target-specific to record properties of the DECL into
538 the associated SYMBOL_REF. */
539 void (* encode_section_info) (tree, rtx, int);
541 /* Undo the effects of encode_section_info on the symbol string. */
542 const char * (* strip_name_encoding) (const char *);
544 /* If shift optabs for MODE are known to always truncate the shift count,
545 return the mask that they apply. Return 0 otherwise. */
546 unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);
548 /* Return the number of divisions in the given MODE that should be present,
549 so that it is profitable to turn the division into a multiplication by
551 unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);
553 /* If the representation of integral MODE is such that values are
554 always sign-extended to a wider mode MODE_REP then return
555 SIGN_EXTEND. Return UNKNOWN otherwise. */
556 /* Note that the return type ought to be RTX_CODE, but that's not
557 necessarily defined at this point. */
558 int (* mode_rep_extended) (enum machine_mode mode,
559 enum machine_mode mode_rep);
561 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
562 bool (* valid_pointer_mode) (enum machine_mode mode);
564 /* True if MODE is valid for the target. By "valid", we mean able to
565 be manipulated in non-trivial ways. In particular, this means all
566 the arithmetic is supported. */
567 bool (* scalar_mode_supported_p) (enum machine_mode mode);
569 /* Similarly for vector modes. "Supported" here is less strict. At
570 least some operations are supported; need to check optabs or builtins
571 for further details. */
572 bool (* vector_mode_supported_p) (enum machine_mode mode);
574 /* True if a vector is opaque. */
575 bool (* vector_opaque_p) (tree);
577 /* Compute a (partial) cost for rtx X. Return true if the complete
578 cost has been computed, and false if subexpressions should be
579 scanned. In either case, *TOTAL contains the cost result. */
580 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
581 not necessarily defined at this point. */
582 bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
584 /* Compute the cost of X, used as an address. Never called with
585 invalid addresses. */
586 int (* address_cost) (rtx x);
588 /* Return where to allocate pseudo for a given hard register initial
590 rtx (* allocate_initial_value) (rtx x);
592 /* Given a register, this hook should return a parallel of registers
593 to represent where to find the register pieces. Define this hook
594 if the register and its mode are represented in Dwarf in
595 non-contiguous locations, or if the register should be
596 represented in more than one register in Dwarf. Otherwise, this
597 hook should return NULL_RTX. */
598 rtx (* dwarf_register_span) (rtx);
600 /* Fetch the fixed register(s) which hold condition codes, for
601 targets where it makes sense to look for duplicate assignments to
602 the condition codes. This should return true if there is such a
603 register, false otherwise. The arguments should be set to the
604 fixed register numbers. Up to two condition code registers are
605 supported. If there is only one for this target, the int pointed
606 at by the second argument should be set to -1. */
607 bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
609 /* If two condition code modes are compatible, return a condition
610 code mode which is compatible with both, such that a comparison
611 done in the returned mode will work for both of the original
612 modes. If the condition code modes are not compatible, return
614 enum machine_mode (* cc_modes_compatible) (enum machine_mode,
617 /* Do machine-dependent code transformations. Called just before
618 delayed-branch scheduling. */
619 void (* machine_dependent_reorg) (void);
621 /* Create the __builtin_va_list type. */
622 tree (* build_builtin_va_list) (void);
624 /* Gimplifies a VA_ARG_EXPR. */
625 tree (* gimplify_va_arg_expr) (tree valist, tree type, tree *pre_p,
628 /* Validity-checking routines for PCH files, target-specific.
629 get_pch_validity returns a pointer to the data to be stored,
630 and stores the size in its argument. pch_valid_p gets the same
631 information back and returns NULL if the PCH is valid,
632 or an error message if not.
634 void * (* get_pch_validity) (size_t *);
635 const char * (* pch_valid_p) (const void *, size_t);
637 /* If nonnull, this function checks whether a PCH file with the
638 given set of target flags can be used. It returns NULL if so,
639 otherwise it returns an error message. */
640 const char *(*check_pch_target_flags) (int);
642 /* True if the compiler should give an enum type only as many
643 bytes as it takes to represent the range of possible values of
645 bool (* default_short_enums) (void);
647 /* This target hook returns an rtx that is used to store the address
648 of the current frame into the built-in setjmp buffer. */
649 rtx (* builtin_setjmp_frame_value) (void);
651 /* This target hook should add STRING_CST trees for any hard regs
652 the port wishes to automatically clobber for an asm. */
653 tree (* md_asm_clobbers) (tree, tree, tree);
655 /* This target hook allows the backend to specify a calling convention
656 in the debug information. This function actually returns an
657 enum dwarf_calling_convention, but because of forward declarations
658 and not wanting to include dwarf2.h everywhere target.h is included
659 the function is being declared as an int. */
660 int (* dwarf_calling_convention) (tree);
662 /* This target hook allows the backend to emit frame-related insns that
663 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
664 engine will invoke it on insns of the form
665 (set (reg) (unspec [...] UNSPEC_INDEX))
667 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
668 to let the backend emit the call frame instructions. */
669 void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
671 /* Perform architecture specific checking of statements gimplified
672 from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
673 is right hand side. Returns true if the statements doesn't need
674 to be checked for va_list references. */
675 bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs);
677 /* This target hook allows the operating system to override the DECL
678 that represents the external variable that contains the stack
679 protection guard variable. The type of this DECL is ptr_type_node. */
680 tree (* stack_protect_guard) (void);
682 /* This target hook allows the operating system to override the CALL_EXPR
683 that is invoked when a check vs the guard variable fails. */
684 tree (* stack_protect_fail) (void);
686 /* Returns NULL if target supports the insn within a doloop block,
687 otherwise it returns an error message. */
688 const char * (*invalid_within_doloop) (rtx);
690 /* DECL is a variable or function with __attribute__((dllimport))
691 specified. Use this hook if the target needs to add extra validation
692 checks to handle_dll_attribute (). */
693 bool (* valid_dllimport_attribute_p) (tree decl);
695 /* Functions relating to calls - argument passing, returns, etc. */
697 bool (*promote_function_args) (tree fntype);
698 bool (*promote_function_return) (tree fntype);
699 bool (*promote_prototypes) (tree fntype);
700 rtx (*struct_value_rtx) (tree fndecl, int incoming);
701 bool (*return_in_memory) (tree type, tree fndecl);
702 bool (*return_in_msb) (tree type);
704 /* Return true if a parameter must be passed by reference. TYPE may
705 be null if this is a libcall. CA may be null if this query is
706 from __builtin_va_arg. */
707 bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
708 tree type, bool named_arg);
710 rtx (*expand_builtin_saveregs) (void);
711 /* Returns pretend_argument_size. */
712 void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
713 tree type, int *pretend_arg_size,
715 bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
716 /* Returns true if we should use
717 targetm.calls.setup_incoming_varargs() and/or
718 targetm.calls.strict_argument_naming(). */
719 bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
721 /* Given a complex type T, return true if a parameter of type T
722 should be passed as two scalars. */
723 bool (* split_complex_arg) (tree type);
725 /* Return true if type T, mode MODE, may not be passed in registers,
726 but must be passed on the stack. */
727 /* ??? This predicate should be applied strictly after pass-by-reference.
728 Need audit to verify that this is the case. */
729 bool (* must_pass_in_stack) (enum machine_mode mode, tree t);
731 /* Return true if type TYPE, mode MODE, which is passed by reference,
732 should have the object copy generated by the callee rather than
733 the caller. It is never called for TYPE requiring constructors. */
734 bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
735 tree type, bool named);
737 /* Return zero for arguments passed entirely on the stack or entirely
738 in registers. If passed in both, return the number of bytes passed
739 in registers; the balance is therefore passed on the stack. */
740 int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
741 tree type, bool named);
743 /* Return the diagnostic message string if function without a prototype
744 is not allowed for this 'val' argument; NULL otherwise. */
745 const char *(*invalid_arg_for_unprototyped_fn) (tree typelist,
746 tree funcdecl, tree val);
748 /* Return an rtx for the return value location of the function
749 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
750 rtx (*function_value) (tree ret_type, tree fn_decl_or_type,
753 /* Return an rtx for the argument pointer incoming to the
755 rtx (*internal_arg_pointer) (void);
758 /* Return the diagnostic message string if conversion from FROMTYPE
759 to TOTYPE is not allowed, NULL otherwise. */
760 const char *(*invalid_conversion) (tree fromtype, tree totype);
762 /* Return the diagnostic message string if the unary operation OP is
763 not permitted on TYPE, NULL otherwise. */
764 const char *(*invalid_unary_op) (int op, tree type);
766 /* Return the diagnostic message string if the binary operation OP
767 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
768 const char *(*invalid_binary_op) (int op, tree type1, tree type2);
770 /* Return the class for a secondary reload, and fill in extra information. */
771 enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
773 struct secondary_reload_info *);
775 /* Functions specific to the C++ frontend. */
777 /* Return the integer type used for guard variables. */
778 tree (*guard_type) (void);
779 /* Return true if only the low bit of the guard should be tested. */
780 bool (*guard_mask_bit) (void);
781 /* Returns the size of the array cookie for an array of type. */
782 tree (*get_cookie_size) (tree);
783 /* Returns true if the element size should be stored in the
785 bool (*cookie_has_size) (void);
786 /* Allows backends to perform additional processing when
787 deciding if a class should be exported or imported. */
788 int (*import_export_class) (tree, int);
789 /* Returns true if constructors and destructors return "this". */
790 bool (*cdtor_returns_this) (void);
791 /* Returns true if the key method for a class can be an inline
792 function, so long as it is not declared inline in the class
793 itself. Returning true is the behavior required by the Itanium
795 bool (*key_method_may_be_inline) (void);
796 /* DECL is a virtual table, virtual table table, typeinfo object,
797 or other similar implicit class data object that will be
798 emitted with external linkage in this translation unit. No ELF
799 visibility has been explicitly specified. If the target needs
800 to specify a visibility other than that of the containing class,
801 use this hook to set DECL_VISIBILITY and
802 DECL_VISIBILITY_SPECIFIED. */
803 void (*determine_class_data_visibility) (tree decl);
804 /* Returns true (the default) if virtual tables and other
805 similar implicit class data objects are always COMDAT if they
806 have external linkage. If this hook returns false, then
807 class data for classes whose virtual table will be emitted in
808 only one translation unit will not be COMDAT. */
809 bool (*class_data_always_comdat) (void);
810 /* Returns true (the default) if the RTTI for the basic types,
811 which is always defined in the C++ runtime, should be COMDAT;
812 false if it should not be COMDAT. */
813 bool (*library_rtti_comdat) (void);
814 /* Returns true if __aeabi_atexit should be used to register static
816 bool (*use_aeabi_atexit) (void);
817 /* Returns true if target may use atexit in the same manner as
818 __cxa_atexit to register static destructors. */
819 bool (*use_atexit_for_cxa_atexit) (void);
820 /* TYPE is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that
821 has just been defined. Use this hook to make adjustments to the
822 class (eg, tweak visibility or perform any other required
823 target modifications). */
824 void (*adjust_class_at_definition) (tree type);
827 /* For targets that need to mark extra registers as live on entry to
828 the function, they should define this target hook and set their
829 bits in the bitmap passed in. */
830 void (*live_on_entry) (bitmap);
832 /* True if unwinding tables should be generated by default. */
833 bool unwind_tables_default;
835 /* Leave the boolean fields at the end. */
837 /* True if arbitrary sections are supported. */
838 bool have_named_sections;
840 /* True if we can create zeroed data by switching to a BSS section
841 and then using ASM_OUTPUT_SKIP to allocate the space. */
842 bool have_switchable_bss_sections;
844 /* True if "native" constructors and destructors are supported,
845 false if we're using collect2 for the job. */
846 bool have_ctors_dtors;
848 /* True if thread-local storage is supported. */
851 /* True if a small readonly data section is supported. */
852 bool have_srodata_section;
854 /* True if EH frame info sections should be zero-terminated. */
855 bool terminate_dw2_eh_frame_info;
857 /* True if #NO_APP should be emitted at the beginning of
859 bool file_start_app_off;
861 /* True if output_file_directive should be called for main_input_filename
862 at the beginning of assembly output. */
863 bool file_start_file_directive;
865 /* True if #pragma redefine_extname is to be supported. */
866 bool handle_pragma_redefine_extname;
868 /* True if #pragma extern_prefix is to be supported. */
869 bool handle_pragma_extern_prefix;
871 /* True if the target is allowed to reorder memory accesses unless
872 synchronization is explicitly requested. */
873 bool relaxed_ordering;
875 /* Returns true if we should generate exception tables for use with the
876 ARM EABI. The effects the encoding of function exception specifications.
878 bool arm_eabi_unwinder;
880 /* Leave the boolean fields at the end. */
883 extern struct gcc_target targetm;
885 #endif /* GCC_TARGET_H */
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